If you have an iPhone with a large display, you may find it difficult to reach the top of the screen with one hand. To make it easier you can lightly double-tap the Home button. Make sure you don’t fully press the Home button, as this will initiate the multitasking view.
The top half of the screen now moves down toward the center to make interacting with items placed here, such as the status bar or the back button, easier to access. To return the view to normal, lightly double-tap the Home button again or tap the top half of the screen.